XML 118 R84.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Common Stock (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Dividends declared per common share | $ 0.6950 | $ 0.6750 | $ 0.6550
Company's subsidiaries net assets restricted from being used to transfer funds to the Company | $ 2,100,000,000 |  |
Credit agreement limitation on company ratio of funded debt to capitalization (excluding subsidiaries) | 65.00% |  |
Company's (excluding its subsidiaries) net assets restricted from use for dividend payments | $ 219,000,000 |  |
Parent company [Member] |  |  |
Shares of common stock reserved for original issuance under the Stock Purchase Plan and K-Plan (in shares) | 15.6 |  |
Centennial [Member] |  |  |
Maximum distributions to the company as a percentage of consolidated net income after taxes, excluding noncash write-downs, for the preceding fiscal year (in hundredths) | 100.00% |  |

X
- Definition Company's (excluding its subsidiaries) net assets restricted from use for dividend payments. + References No definition available. + Details
Name: | mdu_CompanysExcludingItsSubsidiariesNetAssetsRestrictedFromUseForDividendPayments
Namespace Prefix: | mdu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The maximum distributions to the company by the subsidiary as a percentage of consolidated net income after taxes,excluding noncash write-downs, for the preceding fiscal year, pursuant to a covenant under a credit agreement. + References No definition available. + Details
Name: | mdu_MaximumDistributionsToCompanyAsPercentageOfConsolidatedNetIncomeAfterTaxesExcludingNoncashWriteDownsForPrecedingFiscalYearMaximum
Namespace Prefix: | mdu_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ratio of earnings before interest and taxes to interest expense as specified in debt convenants. + References No definition available. + Details
Name: | mdu_RatioOfEarningsBeforeInterestAndTaxesToInterestExpenseAsSpecifiedInDebtConvenants
Namespace Prefix: | mdu_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of restricted net assets of consolidated and unconsolidated subsidiaries as of the end of the most recently completed fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(e)(3)(ii)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph e -Subparagraph 3 -Article 4 + Details
Name: | us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate number of common shares reserved for future issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration